为什么取消列表不将列表分解为最初放入列表的部分？
假设我有以下内容：
v <- zoo(data.frame(a=c(1,2,3), b=c("a","b","c")))
看v，我得到：
> v
a b
1 1 a
2 2 b
3 3 c
> str(v)
‘zoo’ series from 1 to 3
Data: chr [1:3, 1:2] "1" "2" "3" "a" "b" "c"
- attr(*, "dimnames")=List of 2
..$ : NULL
..$ : chr [1:2] "a" "b"
Index: int [1:3] 1 2 3
（1）现在，我尝试将其填充到列表中：
l <- list(one=v, two=v)
然后我尝试取消列出，我本来希望有两个动物园对象。但是相反，我什么都没得到zoo类型的信息：
> unlist(l)
one1 one2 one3 one4 one5 one6 two1 two2 two3 two4 two5 two6
"1" "2" "3" "a" "b" "c" "1" "2" "3" "a" "b" "c"
> str(unlist(l))
Named chr [1:12] "1" "2" "3" "a" "b" "c" "1" "2" "3" "a" "b" "c"
- attr(*, "names")= chr [1:12] "one1" "one2" "one3" "one4" ...
> typeof(unlist(l))
[1] "character"
> class(unlist(l))
[1] "character"
（2）为了理解它，我尝试将1个动物园对象放入列表中：
l <- list(one=v)
当我看着v时，期望获得与上述相同的输出，但令人惊讶的是：
> unlist(l)
one1 one2 one3 one4 one5 one6
"1" "2" "3" "a" "b" "c"
> str(unlist(l))
Named chr [1:6] "1" "2" "3" "a" "b" "c"
- attr(*, "names")= chr [1:6] "one1" "one2" "one3" "one4" ...
> typeof(unlist(l))
[1] "character"
> class(unlist(l))
[1] "character"
我可能没有看到R的一些细微之处，但我不明白我是如何无法从列表中找回原始的动物园对象的（尤其是在1元素列表的情况下）...